new(\%config)
The new() constructor method (implemented by the Template::Base base
class) instantiates a new Template object. A reference to a hash
array of configuration items may be passed as a parameter.
my $tt = Template->new({
INCLUDE_PATH => '/usr/local/templates',
EVAL_PERL => 1,
}) || die $Template::ERROR, "\n";
A reference to a new Template object is returned, or undef on error.
In the latter case, the error message can be retrieved by calling
error() as a class method (e.g. 'Template->error()') or by
examining the $ERROR package variable directly
(e.g. '$Template::ERROR').
my $tt = Template->new(\%config)
|| die Template->error(), "\n";
my $tt = Template->new(\%config)
|| die $Template::ERROR, "\n";
For convenience, configuration items may also be specified as a list
of items instead of a hash array reference. These are automatically
folded into a hash array by the constructor.
my $tt = Template->new(INCLUDE_PATH => '/tmp', POST_CHOMP => 1)
|| die $Template::ERROR, "\n";
process($template, \%vars, $output, %options)
The process() method is called to process a template. The first
parameter indicates the input template as one of: a filename relative
to INCLUDE_PATH, if defined; a reference to a text string containing
the template text; or a file handle reference (e.g. IO::Handle or
sub-class) or GLOB (e.g. \*STDIN), from which the template can be
read. A reference to a hash array may be passed as the second
parameter, containing definitions of template variables.
$text = "[% INCLUDE header %]\nHello world!\n[% INCLUDE footer %]";
# filename
$tt->process('welcome.tt2')
|| die $tt->error(), "\n";
# text reference
$tt->process(\$text)
|| die $tt->error(), "\n";
# GLOB
$tt->process(\*DATA)
|| die $tt->error(), "\n";
__END__
[% INCLUDE header %]
This is a template defined in the __END__ section which is
accessible via the DATA "file handle".
[% INCLUDE footer %]
By default, the processed template output is printed to STDOUT. The
process() method then returns 1 to indicate success. A third
parameter may be passed to the process() method to specify a different
output location. This value may be one of: a plain string indicating
a filename which will be opened (relative to OUTPUT_PATH, if defined)
and the output written to; a file GLOB opened ready for output; a
reference to a scalar (e.g. a text string) to which output/error is
appended; a reference to a subroutine which is called, passing the
output as a parameter; or any object reference which implements a
'print' method (e.g. IO::Handle, Apache::Request, etc.) which will
be called, passing the generated output as a parameter.
Examples:
# output filename
$tt->process('welcome.tt2', $vars, 'welcome.html')
|| die $tt->error(), "\n";
# reference to output subroutine
sub myout {
my $output = shift;
...
}
$tt->process('welcome.tt2', $vars, \&myout)
|| die $tt->error(), "\n";
# reference to output text string
my $output = '';
$tt->process('welcome.tt2', $vars, \$output)
|| die $tt->error(), "\n";
print "output: $output\n";
In an Apache/mod_perl handler:
sub handler {
my $req = shift;
...
# direct output to Apache::Request via $req->print($output)
$tt->process($file, $vars, $req) || do {
$req->log_reason($tt->error());
return SERVER_ERROR;
};
return OK;
}
After the optional third output argument can come an optional
reference to a hash or a list of (name, value) pairs providing further
options for the output. The only option currently supported is
"binmode" which, when set to any true value will ensure that files
created (but not any existing file handles passed) will be set to
binary mode.
# either: hash reference of options
$tt->process($infile, $vars, $outfile, { binmode => 1 })
|| die $tt->error(), "\n";
# or: list of name, value pairs
$tt->process($infile, $vars, $outfile, binmode => 1)
|| die $tt->error(), "\n";
Alternately, the binmode argument can specify a particular IO layer such
as ":utf8".
$tt->process($infile, $vars, $outfile, binmode => ':utf8')
|| die $tt->error(), "\n";
The OUTPUT configuration item can be used to specify a default output
location other than \*STDOUT. The OUTPUT_PATH specifies a directory
which should be prefixed to all output locations specified as filenames.
my $tt = Template->new({
OUTPUT => sub { ... }, # default
OUTPUT_PATH => '/tmp',
...
}) || die Template->error(), "\n";
# use default OUTPUT (sub is called)
$tt->process('welcome.tt2', $vars)
|| die $tt->error(), "\n";
# write file to '/tmp/welcome.html'
$tt->process('welcome.tt2', $vars, 'welcome.html')
|| die $tt->error(), "\n";
The process() method returns 1 on success or undef on error. The error
message generated in the latter case can be retrieved by calling the
error() method. See also CONFIGURATION SUMMARY which describes how
error handling may be further customised.
error()
When called as a class method, it returns the value of the $ERROR package
variable. Thus, the following are equivalent.
my $tt = Template->new()
|| die Template->error(), "\n";
my $tt = Template->new()
|| die $Template::ERROR, "\n";
When called as an object method, it returns the value of the internal
_ERROR variable, as set by an error condition in a previous call to
process().
$tt->process('welcome.tt2')
|| die $tt->error(), "\n";
Errors are represented in the Template Toolkit by objects of the
Template::Exception class. If the process() method returns a false
value then the error() method can be called to return an object of
this class. The type() and info() methods can called on the object to
retrieve the error type and information string, respectively. The
as_string() method can be called to return a string of the form "$type
- $info". This method is also overloaded onto the stringification
operator allowing the object reference itself to be printed to return
the formatted error string.
$tt->process('somefile') || do {
my $error = $tt->error();
print "error type: ", $error->type(), "\n";
print "error info: ", $error->info(), "\n";
print $error, "\n";
};
service()
The Template module delegates most of the effort of processing templates
to an underlying Template::Service object. This method returns a reference
to that object.
context()
The Template::Service module uses a core Template::Context object for
runtime processing of templates. This method returns a reference to
that object and is equivalent to $template->service->context();
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